Hi, I was thinking round some comments that Allen wrote on the section I distributed yesterday and became somewhat confused as to what the scope of data access is for this ogsa data architecture document. I make some assertions below and some of the consequences - any thoughts? What should be ruled in scope and what is out of scope for this version of the document? Mario --- Assertions: 1. a data service represents: i) A single data resource (the data resource may be arbitrarily complex, e.g. it could be a federation but the data service has a single point of contact with the data resource) ii) More than one data resource iii) More than one data service iv) A combination of data resources and data services 2. the data service's data access capability allows: i) Read only access. ii) Read and Write access. 3. data obtained by a data service through a data resource is: i) Returned directly back to the client ii) Materialised and kept at the service side, exposed through another (or the same) data service. iii) Data is delivered to a third party, the client gets a status notification. Consequences: 1. For cases 1 (ii)-(iv) require some naming scheme for the service to determine what data resource/service can be targetted assuming that a message will only ever target a single resource. Most of the entities will have names that already exist. Question: can/should a message be able to target multiple resources? 2. For cases 1 (iii) and (iv) require some service-to-service access mechanism. Is this in scope for data access. 3. For case 2 (ii) Write access will complicate things by a *lot*. Things get even more complicated if cases 1 (ii)-(iv) which may require to operate in some transactional context. 4. For case 3 (i) is kind of weak for transferring large amounts of data. Are cases 3 (ii) and (iii) in scope for data access? You could have an operation that specifies another end point (which need not be a service) to which data should be delivered. Is this in scope? +-----------------------------------------------------------------------+ |Mario Antonioletti:EPCC,JCMB,The King's Buildings,Edinburgh EH9 3JZ. | |Tel:0131 650 5141|mario@epcc.ed.ac.uk|http://www.epcc.ed.ac.uk/~mario/ | +-----------------------------------------------------------------------+